• Applied Chemistry for Engineering
• /
• v.21 no.2
• /
• pp.178-182
• /
• 2010

Simultaneous removal reaction for NOx, soot over Pt catalysts using various $TiO_2$ as support was studied. The catalytic tests ware carried out injectin NO, soot, NO and soot simultaneously on each catalysts. As results, it showed different NOx removal efficiency and soot oxidation rate according to various kinds of $TiO_2$. Onset temperature of soot oxidation has a correlation to $NO_2$ generated for the independently performed NOx. It was investigated that NO to $NO_2$ oxidation was intimately related to crystallite size and surface area, and it has a tremendous impact on Pt aggregation on the catalyst surface and catalyst' reducibility. Therefore, we concluded that major index of the reaction was physico-chemical properties of catalyst' supports.

• Korean Journal of Environmental Agriculture
• /
• v.42 no.4
• /
• pp.427-434
• /
• 2023

Large amounts of organic wastes generated in agricultural environments such as crop residues and livestock manure adversely affect the environment. Anaerobic digestion can reduce the amount of organic wastes and convert them into energy at the same time. Efforts are being made to further increase the energy conversion efficiency by using co-anaerobic digestion using two or more substrates. Tomatoes, rice straw, cattle manure, and cattle feces (CF) were used as substrates for anaerobic digestion. Each substrate was subjected to anaerobic digestion and the cumulative biochemical methane production potential was measured, and the biodegradability was calculated. Based on the methane production, CF and tomato were further used for co-anaerobic digestion at different mixing ratios. Among the CF:tomato ratios of 1:1, 1:2, and 2:1, 1:2 produced the most methane and the synergy index was greater 1 indicating that the co-digestion of CF and tomato improved the methane production. Overall, the results showed that the methane production from cattle manure can be improved using tomato residues.

• Journal of Korean Society on Water Environment
• /
• v.39 no.6
• /
• pp.465-474
• /
• 2023

The chemical composition and molecular weight characteristics of dissolved organic matter (DOM) exert a profound influence on the efficiency of organic matter removal in water treatment systems, acting as efficiency predictive indicators. This research evaluated the primary chemical and molecular weight properties of DOM derived from diverse sources, including rivers, lakes, and biomasses, and assessed their relationship with the efficiency of coagulation/flocculation treatments. Dissolved organic carbon (DOC) removal efficiency through coagulation/flocculation exhibited significant correlations with DOM's hydrophobic distribution, the ratio of humic-like to protein-like fluorescence, and the molecular weight associated with humic substances (HS). These findings suggest that the DOC removal rate in coagulation/flocculation processes is enhanced by a higher presence of HS in DOM, an increased influence of externally sourced DOM, and more presence of high molecular weight compounds. The results of this study further posit that the efficacy of water treatment processes can be more accurately predicted when considering multiple DOM characteristics rather than relying on a singular trait. Based on major results from this study, a predictive model for DOC removal efficiency by coagulation/flocculation was formulated as: 24.3 - 7.83 × (fluorescence index) + 0.089 × (hydrophilic distribution) + 0.102 × (HS molecular weight). This proposed model, coupled with supplementary monitoring of influent organic matter, has the potential to enhance the design and predictive accuracy for coagulation/flocculation treatments targeting DOC removal in future applications.

• Clinical Nutrition Research
• /
• v.11 no.2
• /
• pp.110-119
• /
• 2022

Musculoskeletal pains (MPs), defined as persistent or recurrent pain, is a complex health problem. High overall calorie and fat intake have been related to obesity and MPs. Dietary energy density (DED), defined as energy content of food and beverages (in kcal) per unit total weight, has been associated with chronic muscle, cartilage, bone damage and pain. Thus, the purpose of this study is to investigate the association between DED and MPs in adult men and women. A total of 175 men and women (> 18 years) with MP participated in the study. A validated short form physical activity (PA) questionnaire, demographic, and McGill Pain Questionnaire were used. Anthropometric measurements were evaluated via standard protocols. Furthermore, a seven-day 24-hour recall of diet was used to determine the dietary intake. Total DED was calculated and divided into quartiles. Linear regression was used to discern the association between DED and MPs in adults. Participants assigned in the highest category of DED were characterized by lower intake of potassium, magnesium, vitamin C, folate, and fiber. However, results showed displayed higher intake of sodium, vitamin E, vitamin B3, fat, protein, cholesterol, saturated fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids (p < 0.001). Finally, after adjustment for confounders such as age, gender, PA, body mass index, waist circumference, education, job, marital status, history of some chronic diseases and vitamin C supplementation, a significant positive association was detected between DED and pain intensity. There was no significant association between DED and pain frequency in all models.

• Nuclear Engineering and Technology
• /
• v.56 no.9
• /
• pp.3804-3811
• /
• 2024

The study focuses on creating new boro-silicate glasses doped with SnO₂ for radiation shielding. It examines how substituting Na₂O with SnO₂ affects their structural, optical, and shielding properties. Density increases from 2.406 to 2.488 g/cm³ with rising SnO₂, measured via the Archimedes Method. The examination for the glassy phase was performed using the XRD diffractometer. UV/Vis spectrophotometer analysis reveals reduced refractive index (2.412-1.976) and increased optical absorption-band gap (direct: 3.648-5.662 eV; indirect: 2.994-5.163 eV) with SnO₂ concentrations of 0-9 mol.%). The effectiveness of the radiation shielding was assessed over the 0.059-1.408 MeV gamma-ray energy interval. The analysis demonstrates that when the concentration of SnO₂ increases, the synthesized glasses' linear attenuation coefficient improves. As the SnO₂ content was raised between 0 and 9 mol%, the linear attenuation coefficient rose between 0.489 and 2.892 cm^-1 (at energy of 0.059 MeV) and between 0.126 and 0.128 cm^-1 (at energy of 1.408 MeV), respectively. As the SnO₂ content was raised between 0 and 9 mol%.

• Journal of Energy Engineering
• /
• v.20 no.1
• /
• pp.63-76
• /
• 2011

This paper studies the impact of Korean introduction of the Generalized System of Preferences(GSP) to developing countries, which are continuously arguing to support research and development for reducing greenhouse gas(GHG) emission with developed countries in the Conference of the Parties(COP) of UNFCCC. This paper is focusing on the expecting effects of trade and GHG emission reduction when Korea provides GSP to Indonesia, Brazil, and Ethiopia, which are selected in the first session of Global Green Growth Institute(GGGI). This paper uses the methodology of the intra-industry trade index multiplied by Korean import-induced coefficients. To Indonesia, Korean probable GSP would benefit exports of Indonesian agriculture, forestry, fishery, and livestock farming industries, which would contribute to Indonesian reduction of GHG emission. To Brazil, the exports to Korea would increase in the GHG sensitive industries such as metal, fat, oils, food, and beverage industries. Ethiopia belongs to the least developed countries. So Korean GSP would support the exports and GHG reduction in Ethiopian agriculture, forestry, fisheries, textiles, and leather industries. Without conflicting most favored nation treatment(MFN) principle in WTO, the introduction of GSP would be a good compensation for GHG reduction to developing countries.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.26 no.2
• /
• pp.75-84
• /
• 2018

In this study, the analysis of torrefaction products was carried out for fueling of sewage sludge. The mixed samples were composed as follows : 50% of sewage sludge and 50% of rice husk and CR(Coffee Residue). In this experiment, the reaction time(30min, 60min) and temperature($200^{\circ}C$, $250^{\circ}C$, $300^{\circ}C$) were expressed as a single variable using SF(Severity Factor). As a result, it was confirmed that as the SF increased, the heating value and fuel ratio increased, but the CI(Combustibility Index) decreased. The heating value was similarly increased as CR(Coffee Residue) and SF increased. The fuel ratio range of mixed samples was equal to that of lignite(0.5~1.0) in case of SF lower than 6.19 and that of bituminous coal(1.0~1.8) in case of SF higher than 7.36 or above. The CI showed a stable range(3,000~5,500kcal/kg) in low SF as the content of mixed samples contained more rice husk than CR.

• Journal of Energy Engineering
• /
• v.18 no.4
• /
• pp.246-257
• /
• 2009

Regarding climate change, the most significant challenge the world faces is achieving the goal of stabilizing the global concentration of greenhouse gases. However, this cannot be accomplished by greenhouse gas reduction efforts of developed countries alone. In this context, a "sectoral approach" has been brought up as a way to overcome the limit of the Kyoto Protocol and induce the participation of developing countries. This paper focuses on the different types of sectoral approaches that have been suggested so far, and their criteria, scope and effectiveness. It therefore explores the potential each approach has as a policy alternative under the post-2012 scheme. On top of that, with the possibility of these sectoral approaches becoming strong future policy alternatives in mind, this paper also analyzes their applicability to the Korean industry. For the steel, petrochemical and oil industries - in which energy efficiency exceeds the world average- a technology-based approach is proposed as an alternative. For the cement, paper and power generation industries - in which energy efficiency is about the same as the global average - a sectoral crediting mechanism or an index-based approach or a sector-wide transnational approach are proposed as alternatives. Lastly, this paper suggests a future research direction for their adoption and implementation.

• Polymer(Korea)
• /
• v.36 no.5
• /
• pp.549-554
• /
• 2012

It was known that triphenyl phosphate wasn't homogeneously dispersed in HDPE/EPDM/boron carbide blends, which caused the decrease in mechanical properties. HDPE, EPDM, boron carbide, and triphenyl phosphate were blended with PE-g-MAH(polyethylene-graft-maleic anhydride) as a compatiblizer for improving the miscibility of triphenyl phosphate. Tensile strength of HDPE/EPDM/boron carbide blends decreased with increasing the contents of triphenyl phosphate for flammability. However, the mechanical properties of HDPE/EPDM/boron carbide/triphenyl phosphate blends increased by the addition of compatiblizer because triphenyl phosphate was homogeneously mixed in the blend system. The homogeneous dispersibility of triphenyl phosphate was confirmed by using scanning electron microscopy (SEM). Increased thermal stability and flammability derived from high miscibility of triphenyl phosphate were confirmed by the results of thermogravimetric analysis (TGA) and limiting oxygen index (LOI). A self-extinguishing HDPE/EPDM/boron carbide/triphenyl phosphate blend was successfully fabricated with more than 21% LOI.

• Journal of Radiation Protection and Research
• /
• v.41 no.4
• /
• pp.395-401
• /
• 2016

Background: Liquid scintillation counters (LSCs) are commonly used as an analytical method for detecting $^{222}Rn$ in groundwater because they involve a simple sample pretreatment and allow high throughout with an autosampler. The Quantulus 1220 is the best-selling LSC in Korea, but its production was stopped. Recently, a new type of LSC, the 300SL, was introduced. In this study, the 300SL was compared with the Quantulus 1220 in order to evaluate the ability of each apparatus to detect $^{222}Rn$ in groundwater. Materials and Methods: The Quantulus 1220 and 300SL were used to detect the presence of $^{222}Rn$. Radon gas was extracted from a groundwater sample using a water-immiscible cocktail in a LSC vial. The optimal analytical conditions for each LSC were determined using a $^{222}Rn$ calibration source prepared with a $^{226}Ra$ source. Results and Discussion: The optimal pulse shape analysis level for alpha and beta separation was 80 for the Quantulus 1220, and the corresponding pulse length index was 12 in the 300SL. The counting efficiency of the Quantulus 1220 for alpha emissions was similar to that of the 300SL, but the background count rate of the Quantulus 1220 was 10 times lower than that of the 300SL. The minimum detectable activity of the Quantulus 1220 was $0.08Bq{\cdot}L^{-1}$, while that of the 300SL was $0.20Bq{\cdot}L^{-1}$. The analytical results regarding $^{222}Rn$ in groundwater were less than 10% different between these LSCs. Conclusion: The 300SL is an LSC that is comparable to the Quantulus 1220 for detecting $^{222}Rn$ in groundwater. Both LSCs can be applied to determine the levels of $^{222}Rn$ in groundwater under the management of the Ministry of Environment.